Heat stabilized antistatic polyamides

ABSTRACT

Tensile strength loss on heating is reduced, in polycarbonamides containing between 0.1 and 20.0 weight percent polyalkoxylated triglyceride of a fatty acid containing from 10 to 30 carbon atoms, by adding from 0.01 to 2.0 weight percent of a sterically hindered phenol.

United States Patent Inventor Appl. No.

Filed Patented Assignee Continuation-impart of application Ser. No.

759,210, Sept. 11, 1968, now abandoned which is a continuation-in-partof application Ser. No. 732,826, May 29, 1968, now abandoned which is acontinuation-in-part of application Ser. No. 674,662, Oct. 1 l, 1967,now Patent No. 3,388,104, which is a continuation-in-part oi applicationSer. No. 579,509, Sept. 15, 1966, now abandoned which is acontinuation-in-part of application Ser. No. 422,822, Dec. 31, 1964, nowabandoned. This application Feb. 25, 1970, Ser. No. 14,206

The portion of the term of the patent subsequent to June 11, 1985, hasbeen disclaimed.

[54] HEAT STABILIZED ANTISTATIC POLYAMIDES 11 Claims, No Drawings [52]U.S.Cl 260/1811, 260/45.7 R, 260/45.75 R, 260/45.95 R, 260/78 R [51]lnt.Cl C08g 51/58 [50] Field of Search 260/l8 N, 45.95, 45.85, 78,18 R,45.7, 78 R [56] References Cited UNITED STATES PATENTS 3,502,613 3/l970Berger 260/45.8 3,493,633 2/1970 Lange.... 260/45.95 3,389,119 6/1968Sherill 260M595 3,388,104 6/1968 Crovatt 260/3 [.4 3,285,855 ll/l966Dexter et al. 260/45.85 3,274,151 9/l966 Settele 260/4595 PrimaryExaminer-Donald E. Czaja Assistant Examiner-Eugene C. RzucidloAnomeyJohn W. Whisler ABSTRACT: Tensile strength loss on heating isreduced, in polycarbonamides containing between 0.l and 20.0 weightpercent polyalkoxylated triglyceride of a fatty acid containing from 10to 30 carbon atoms, by adding from 0.0l to 2.0 weight percent of asterically hindered phenol.

HEAT STABILIZED ANTISTATIC POLYAMIDES This is a continuation-in-part ofapplicants copending application, Ser. No. 759,210, filed Sept. 1 1,1968, which in turn is a continuation-in-part of applicants Ser. No.732,826, filed May 29, 1968 both now abandoned which is in turn acontinuation-in-part of Ser. No. 674,662 filed Oct. 1 1, 1967, now US.Pat. No. 3,388,104 which application is in turn a continuation-in-partof Ser. No. 579,509 filed Sept. 15, 1966, now abandoned which is in turna continuation-in-part of Ser. No. 422,822 filed Dec. 31, 1964, nowabandoned.

The invention relates to an additive for a polycarbonamide compositionhaving antistatic and antisoil properties, wherein the additive reducesloss of strength upon heating.

US. Pat. No. 3,388,104, discloses and claims polycarbonamides havinggreatly improved permanent antistatic properties, produced byincorporating into the molten polymer prior to a filament formation from0.1 to 20.0 weight percent of a polyalkoxylated triglyceride of asaturated fatty acid having from to 30 carbon atoms. The disclosure ofthe above noted application is incorporated herein by reference.Unfortunately, the resulting antistatic filaments tend to lose tensilestrength on exposure to elevated temperatures for short periods of time,such as during heat setting of fabrics formed from the yarn. it has beendiscovered that the loss in tensile strength can be reduced by thefurther addition of sterically hindered phenols as more fully set forthbelow.

Accordingly, a primary object of the invention is to provide additivesfor reducing strength loss upon heating in polycarbonamides containingpolyalkoxylated triglycerides. A further object is to provide methodsfor incorporating such additives into filaments, and to provide for suchfilaments which retain a greater proportion of their original tensilestrength after heatmg.

Other objects of the invention will in part be obvious and will in partappear hereinafter.

The objects of the invention are achieved by blending the hinderedphenol, polymer, and triglyceride prior to filament formation, i.e.,prior to melt spinning. As more fully set forth in my above notedapplication, the polymeric substances with which this invention isconcerned are synthetic high molecular weight fiber-formingpolycarbonamides of the general type characterized by the presence ofrecurring carbonamide groups as an integral part of the polymer chain,and wherein such groups are separated by at least two carbon atoms. Theyare further characterized by high melting point, pronouncedcrystallinity and insolubility in most solvents except mineral acids,formic acid and phenols. Upon hydrolysis with strong mineral acids thepolymers revert to the reactants from which they were formed.

The polyamides of this type are usually made by heating either (a)substantially equimolecular proportions of a diamine and dicarboxylicacid or (b) various amino acids and amide-forming derivatives thereofuntil the material has polymerized to the fiber-forming stage, whichstage is not generally reached until the polyamide has an intrinsicviscosity ofat least 0.4, the intrinsic viscosity being defined as:

in the preparation of a polyamide, it is usually desirable that thedicarboxylic acid be introduced into the reaction as a preformed salt,i.e., diamine salt. However, this is a matter of convenience only sincethe dicarboxylic acid and a corresponding molecular quantity of diaminemay be in the form of uncombined diacid-diamine when brought into thereaction zone.

The synthetic linear polycarbonamides of this invention may be prepared,spun and drawn under conventional, polyamide-forming productionconditions. In addition to the aforedescribed antistatic agents,delusterants, antioxidants, plasticizers, viscosity stabilizers, andother like materials may be used in the preparation of the polyamides ofthis invention.

According to the invention there is blended into thepolycarbonamide-triglyceride system from 0.01 and 2.0 weight percent(based on the weight of the polymer) hindered phenolic materials whichare satisfied by the following general formula:

in which at least one of R and R is selected from the class consistingof a branched C to C alkyl radical (a radical containing between threeand eight carbon atoms), an aralkyl radical such as benzyl, and ahydroxyaralkyl radical wherein the hydroxyaryl portion contains as asubstituent a branched C to C., alkyl group attached ortho to thehydroxy group. The preferred hydroxyaralkyl radical is a3-tert-butyl-2-hydroxybenzyl group, although the hydroxy group can be inthe three or four positions if desired. Although the other of R and Rcan be hydrogen, methyl or ethyl, preferably both of R and R areselected from the class noted above.

R R, and R can be hydrogen, alkyl, or other substituents which arechemically inert to the extruded composition under spinning conditions,and substantially inert at 200 C. in air for 2 minutes. The aryl portionof the aralkyl radical (whether or not a phenolic hydroxy group isincluded therein) can likewise contain such inert further substituents.

The phenols are preferably melted and blended into the polyalkoxylatedtriglyceride, which is then blended into the molten polycarbonamide justprior to spinning. However, they can be added to the materials whichwill be reacted to form the polymer, or can be coated onto polymer flakewhich is to be melted and extruded, or can be separately blended intothe molten polymer before or'after blending in the polyalkoxylatedtriglyceride.

' EXAMPLE] This example illustrates the preparation of filaments of thestatic resistant polyamide disclosed in US. Pat. No. 3,388,104, namely,polyhexamethylene diammonium adipate (nylon 66 salt) polyblended with200 molar polyethoxylated hydrogenated castor oil. These yarns will beused as standard of comparison for strength retention properties withpolyamides of the same type modified in accordance with this invention.

The following materials are added to a stainless steel highpressureautoclave equipped with a mechanical stirrer: parts of hexamethylenediammonium adipate, 50 parts of water, 50 ppm. of manganese added in theform of manganous hypophosphite monohydrate salt, and 10.0 weightpercent (based on the weight of unmodified polyamide) of hydrogenatedcastor oil polyethoxylated with 200 moles of ethylene oxide per mole ofthe glyceride. The autoclave is then purged of air using purifiednitrogen and, while stirring, the temperature in the autoclave is slowlyraised until values of to 200 C. are reached. At this point 2.0 weightpercent (based on the weight of unmodified polyamide) of titaniumdioxide is added. Next the temperature and pressure in the autoclave areraised until 220 C. at 250 p.s.i.g. pressure are reached. Thetemperature is then further increased while steam condensate is removeduntil the temperature reaches 243 C. At this point the pressure isslowly reduced over a 25- minute period to atmospheric pressure whilethe temperature of the molten polymer is raised to 278 C., at whichpoint the polymer melt is allowed to equilibrate for 30 minutes.

The resultant molten polymer is melt extruded through a 14-holespinneret to yield white multifilament yarn. The yarn is drawn 4.43times its original length and has a tenacity of 5.69 grams per denier atan ultimate elongation of 24.] percent. Resistance of this yarn tostrength loss upon being exposed to high temperatures is shown in tableI.

The final polymer thus obtained is melt spun through a l4- holespinneret to yield a white multifilament yarn. 'l'hc yarn is drawn 4.55times its original length and has a tenacity of 4.32 grams per denier atan ultimate break elongation of 28.0 per EXAMPLE u 5 cent. Resistanceotthis yarn to strength loss upon exposure to elevated temperatures isshown in table I and comparison made against control yarn otexal'nple I.

EXAMPLE V Polymer is prepared by employing procedures and techniquesidentical to those used in example I, except that 0.5 weight percent(based on the weight of unmodified polymer) of 2,2-methylene bis(4-methyl-6-tert-butylphenol) is added to the polymer preparationingredients.

The final polymer thus obtained is melt spun through a 14- holespinneret to yield a white multifilament yarn. The yarn is drawn 4.51times its original length and has a tenacity of 4.23 grams per denier atan ultimate break elongation of 27.1 percent. Resistance of this yarn tostrength loss upon exposure to elevated temperatures is shown in table Iand comparison made against control yarn of example I.

EXAMPLE V1 Polymer is prepared by employing techniques and proceduresidentical to those employed in example 1, except that 0.1 weight percent(based on the weight of the unmodified polymer) of 2,2'-methylene, bis(4-methyl-6-tertbutyl phenol) is added to the polymer preparationingredients.

The final polymer is spun through a l4-hole spinneret to yield a whitemultifilament yarn. The yarn is drawn 4.51 times its original length andhas a tenacity of 4.24 grams per denier and an ultimate break elongationof 27.1 percent.

Testing of the yarns prepared in the foregoing examples is conducted bydetermining the amount of strength loss on elevated temperatureexposure.

EXAMPLE. vn

A batch of polymer is prepared under conditions identical to thoseemployed in example I, except that 0.l weight percent (based on theweight of unmodified polymer) of hindered phenolic compound 2,4,6-tris(3-tert-butyl-5 -methyl-2- hydroxybenzyl) phenol is added to the polymeringredients. The structure of this phenol is as follows:

A batch of polymer is prepared under conditions identical to thoseemployed in example I, except that 0.05 weight percent (based on theweight of unmodified polymer) of the hindered phenol,l,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4- hydroxybenzyl) benzeneis added to the polymer preparation ingredients. This compound has thefollowing structural formain:

0"(CH8)3 (C DP H 0 0 H3 0 H (CHa)aC CH: a C(C a)a H O CHa This finishedpolymer is then melt spun through a l4-hole EXAMPLE lll Polymer isprepared by employing procedures and techniques identical to those usedin example 1, except that 0.5 weight percent (based on the weight ofunmodified polymer) of l,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl) benzene is added to the polymer preparation ingredients.

The final polymer thus obtained is melt spun through a 14- holespinneret to yield a white multifilament yarn. The yarn is drawn 4.50times its original length and has a tenacity of 4.67 grams per denier atan ultimate break elongation of 29.0 percent. Resistance of this yarn tostrength loss upon exposure to elevated temperatures is shown in table Iand comparison made against control yarn of example I. t

CH3 C (CH3)aC- CH2- CH3 C(CHa):

EXAMPLE lV Polymer is prepared by employing procedures and techniquesidentical to those used in example I, except that 0.5 weight percent(based on the weight of unmodified polymer) OF4,4-butylidenebis(-tert-butyl-m-cresol) is added to the polymerpreparation ingredients. This compound has the following formula:

CHa C (CH The finished polymer is melt spun through a l4-hole spinneretto yield a white multifilament yarn. The yarn is drawn 4.4 times itsoriginal length having a tenacity of 4.80 grams per denier at ultimatebreak elongation of 30.0 percent.

CH a)a I C (C Hz) a OH; I Strength retention of this yarn after exposureto 200 C. for 5 minutes is shown in table 1.

CH3 TABLE] IOIOIIII "A16 TABLE 2 i: Tensile Strength Retained I(control) 47.3 5 Alter 5 Mins.

" (can Example Exposure At 220 C. III (test) I000 IV (teal) 94.2

V (tent) 79.5 Vlli (control) 45.0 V! (tent) 52.3 IX (test) 900 VI!(lent) 75.0 10 X (test) 88.0

EXAMPLE Vlll EXAMPLE X] This example illustrates the preparation offilaments of o y e was p pa ed by employing Procedure and staticresistant poly-e-caproamide (nylon 6) polyblended with 200 molarpolyethoxylated hydrogenated castor oil. These yarns are used asstandard of comparison for heat stability properties with polyamides ofthe same type, modified in accordance with this intention.

The following materials are added to a stainless steel autoclave,equipped with a mechanical stirrer:

130 parts of e-caprolactam, 5 parts of water, 10 ppm. of manganese(added in the form of manganous hypophosphitemonohydrate salt), and 10.0weight percent (based on weight of unmodified polyamide) of 200 molarpolyethoxylated hydrogenated castor oil (glyceride ester). The autoclaveis then purged of air using purified nitrogen and with stirring, thetemperature in the autoclave is slowly raised until values of l90-200 C.are reached. At this point 0.3 weight of percent (based on the weight ofunmodified polyamide) of titanium dioxide is added. The temperature andpressure in the autoclave are then raised to 220 C and 250 p.s.i.g. withremoval of steam condensate. Further temperature increase to 243 C. iscarried out at which point the pressure is gradually lowered over a-minute period to atmospheric pressure while the melt temperaturecontinues to increase to 280 C. The polymer melt is then allowed toequilibrate in the molten state for minutes during which time thetemperature is lowered to 240 C.

The resultant molten polymer is melt spun through a 14- hole spinneretto yield white yarn. The yarn is drawn 4.00 times its original lengthhaving a tenacity of 5.5 grams per denier at ultimate elongation of 30.0percent.

Strength retention of this yarn after exposure to 200 C. for 5 minutesis given in table 2.

EXAMPLE lX This batch of polymer is prepared under the same conditionsas described in example Vlll, except that 0.5 weight percent (based onthe weight of unmodified polymer) of 1,3,5- trimethyl-2,4,6-tris-( 3 ,5-di-tert-butyl-4-hydroxybenzyl) benzene is added to the polymerpreparation ingredients.

The polymer obtained is melt spun through a l4-hole spinneret to yieldwhite yarn. The yarn is then drawn 4.00 times its original length havinga tenacity of 5.7 grams per denier at ultimate elongation of 29.1percent.

Strength retention of this yarn after exposure to 200 C. for 5 minutesis related in table 2.

EXAMPLE X Polymer is prepared by employing procedure and techniquesidentical to those used in example Vlll, except that 0.5 weight percent(based on the weight of unmodified polymer) of4,4'-butylidenebis-(6-tert-butyl-mucresol) was added to the polymeringredients.

The polymer obtained is melt spun through a l4-hole spinneret to yieldwhite yarn. The yarn is then drawn 4.00 times its original length havinga tenacity of 5.6 grams per denier at ultimate elongation of 30.0percent.

Strength retention of this yarn after exposure to 200 C. for 5 minutesis related in table 2.

The finished polymer thus obtained was melt spun through a 14-holespinneret to yield a white multifilament yarn. The yarn was drawn 4.50times its original length and had a tenacity of 3.86 grams per denier atan ultimate break elongation of 21.0 percent. Resistance of this yarn tostrength loss upon exposure to elevated temperatures was determined andis given in table 3.

EXAMPLE Xll Polymer was prepared by employing the procedure andtechniques of example XI, except that 0.1 weight percent o.w.p. of theester used in example Xl was dissolved in the polyethoxylated,hydrogenated castor oil. The resulting yarn was drawn 4.50 times itsoriginal length and had a tenacity of 4.54 grams per denier at anultimate break elongation of 29.1 percent. Resistance of this yarn tostrength loss upon exposure to elevated temperatures was determined andis given in table 3.

EXAMPLE Xlll Polymer was prepared in the same manner as in example Xl,except that 0.2 weight percent o.w.p. of the ester used in example Xlwas dissolved in the polyethoxylated, hydrogenated castor oil. Theresulting yarn was drawn 4.50 times its original IOIOIZ90 length and hada tenacity of 4.39 grams per denier at an ultimate break elongation of26.2 percent. Resistance of this yarn to strength loss upon exposure toelevated temperatures was determined and is given in table 3.

EXAMPLE XIV TABLE 3 'k Tensile Strength Retained After 5 Mins.

Example 200 C, Exposure (control) 47.3 Xl (test) 68.] Xll (test) 72.lXlll (lest) 7L6 XlV(test) 91.8

Addition of more than 2.0 percent of the phenol is generally undesirablebecause of discoloration of the resulting yarn.

What is claimed is:

l. A fiber-forming synthetic linear polycarbonamide having recurringamide groups as an integral part of the main polymer chain, and whereinsaid groups are separated by at least two carbon atoms, saidpolycarbonamide containing:

A. from 0.1 to about 20.0 weight percent, based on the weight of saidpolycarbonamide, of a polyalkoxylated triglyceride of saturated fattyacid having ID to 30 carbon atoms, wherein the polyalkoxy portion has amolecular weight of between about 2,000 and 22,000; and

B. from 0.0] to 2.0 weight percent of a phenol selected from the groupconsisting ofl,3,5-trimethyl-2,4,6-tris(3.5-ditert-butyl-4-hydroxybenzyl )-benzene,4,4 '-butylidenebis(-tert-butyl-m-cresol), 2,2'-methylenebis(4-methyl-6-tert-butyl-phenol), 2,4,6-tris(3-tert-butyl-5-methyl-Z-hydroxy-benzyl)-phen0l and pentaerythritoltetra(3,5-di-tert-butyl-4-hydroxy-phenyl)propionate.

2. A fiber-forming synthetic linear polycarbonamide as defined inclaim 1. wherein said polyalkoxylated glyceride is polyalkoxylatedhydrogenated castor oil.

3. A fiber-forming synthetic linear polycarbonamide as defined in claim2, wherein said polyalkoxylated hydrogenated castor oil is present in anamount of from L0 to 15.0 weight percent, based on the weight of saidpolycarbonamide.

4. The fiber-forming synthetic linear polycarbonamide as set forth inclaim 3, wherein said polycarbonamide is polyhexamethylene adipamide.

5. A textile fiber comprising the polycarbonamide as defined in claim 1.

6. A textile fiber comprising the polycarbonamide as defined in claim 3.

7. A fiber-forming synthetic linear polycarbonamide having recurringamide groups as an integral part of the main polymer chain, wherein saidgroups are separated from one another by at least two carbon atoms, andcontaining incorporated therein from 0.] to 20 percent by weight, basedon the weight of said polycarbonamide, of a polyalkoxylated triglycerideof a saturated fatty acid having 10 to 30 carbon atoms, wherein thepolyalkoxy portion has a molecular weight of between about 2,000 and20,000, and containing dissolved therein between about 0.0l to 2 percentby weight, based on the weight of said polycarbonamide, of the compoundof the structure:

8. The polycarbonamide as defined in claim 7 wherein saidpolyalkoxylated triglyceride is polyethoxylated hydrogenated castor oil.

9. The polycarbonamide as defined in claim 8 wherein said castor oil ispresent in an amount between about L0 and l5 percent by weight, based onthe weight of said polycarbonamide.

10. The polycarbonamide of claim 9, wherein said polycarbonamide ispolyhexamethylene adipamide.

11. A textile fiber comprising the polycarbonamide of claim 7.

2. A fiber-forming synthetic linear polycarbonamide as defined in claim1, wherein said polyalkoxylated glyceride is polyalkoxylatedhydrogenated castor oil.
 3. A fiber-forming synthetic linearpolycarbonamide as defined in claim 2, wherein said polyalkoxylatedhydrogenated castor oil is present in an amount of from 1.0 to 15.0weight percent, based on the weight of said polycarbonamide.
 4. Thefiber-forming synthetic linear polycarbonamide as set forth in claim 3,wherein said polycarbonamide is polyhexamethylene adipamide.
 5. Atextile fiber comprising the polycarbonamide as defined in claim
 1. 6. Atextile fiber comprising the polycarbonamide as defined in claim
 3. 7. Afiber-forming synthetic linear polycarbonamide having recurring amidegroups as an integral part of the main polymer chain, wherein saidgroups are separated from one another by at least two carbon atoms, andcontaining incorporated therein from 0.1 to 20 percent by weight, basedon the weight of said polycarbonamide, of a polyalkoxylated triglycerideof a saturated fatty acid having 10 to 30 carbon atoms, wherein thepolyalkoxy portion has a molecular weight of between about 2,000 and20,000, and containing dissolved therein between about 0.01 to 2 percentby weight, based on the weight of said polycarbonamide, of the compoundof the structure:
 8. The polycarbonamide as defined in claim 7 whereinsaid polyalkoxylated triglyceride is polyethoxylated hydrogenated castoroil.
 9. The polycarbonamide as defined in claim 8 wherein said castoroil is present in an amount between about 1.0 and 15 percent by weight,based on the weight of said polycarbonamide.
 10. The polycarbonamide ofclaim 9, wherein said polycarbonamide is polyhexamethylene adipamide.11. A textile fiber comprising the polycarbonamide of claim 7.